Abstract: This rulemaking action would revise the rule for implementation of the 8-hour ozone national ambient air quality standard (NAAQS) to address partial vacatur by the U.S. Circuit Court of Appeals for the District of Columbia Circuit. The rulemaking would remove the portions of the regulatory text vacated by the Court, specifically: (1) The provision that places some 8-hour ozone nonattainment areas under title I, part D, subpart 1, of the CAA; (2) remove the exemption from anti-backsliding for the following three obligations under the now-revoked 1-hour ozone NAAQS:
- New source review;
- CAA Section 185 penalty fees for severe and extreme areas that fail to attain the 1-hour standard by their attainment date; and
- Contingency measures for failure to attain the 1-hour standard or make reasonable progress toward attainment.
The rule would also address: (1) The classification system for nonattainment areas that the implementation rule originally covered under Clean Air Act (CAA) title I, part D, subpart 1; and (2) contingency measures that apply as anti-backsliding measures under the now-revoked 1-hour standard. The rule would also remove an obsolete provision in the 1-hour ozone standard itself (40 CFR 50.9(c)).